Not applicable
(1) Field of the Invention
The present invention relates to a test fixture which allows the assessment of chemical attack on thick elastomeric materials without the introduction of differences due to sample preparation and to a process of using the test fixture.
(2) Description of Prior Art
Various devices have been used in the prior art for determining the properties of sheet materials. Some of these devices are illustrated in U.S. Pat. Nos. 4,406,743 to Gunderson, 4,552,042 to Barker et al., 5,311,767 to Mathews et al., 6,085,579 to Herrlein, and 6,095,000 to Esclar et al. The Gunderson patent discloses a method and apparatus for edgewise compression testing of flat sheets. The Barker et al. and Mathews et al. patents each disclose the clamping of an elastomeric sheet to be tested between two dies. The Herelein patent discloses a method for assessing absorbent structures which utilizes a fluid filled cylinder disposed on top of the structure to be evaluated. The Esclar et al. patent describes a method and apparatus for feeding a treatment liquid to a sample.
The assessment of chemical attack on thick section elastomeric materials has been difficult to perform due to the need to extract small samples from the thick section for testing. Often, methods used to remove samples for testing, directly affect the results of the material tests due to the introduction of small surface defects such as machining marks, heat which changes the cure of the material, and swell introduced during water jet cutting.
Thus, there remains a need for a non-intrusive test for sheets of elastomeric materials.
Accordingly, it is an object of the present invention to provide a test fixture which allows the assessment of chemical attack on thick materials without the introduction of differences due to sample preparation.
It is a further object of the present invention to provide a test fixture as above which allows the assessment of chemical attack on thick elastomeric materials.
It is yet a further object of the present invention to provide a process for allowing the assessment of chemical attack on thick materials.
The foregoing objects are attained by the test fixture and the process of the present invention.
In accordance with the present invention, a test fixture is provided which broadly comprises a cylinder having an interior space for receiving at least one sheet of material, such as a sheet of elastomeric material, to be tested, and a piston movable relative to the cylinder for applying a holding force to the at least one sheet. The piston has a through hole for allowing a test medium to come into contact with the at least one sheet.
In accordance with the present invention, a process for allowing the assessment of chemical attack on thick elastomeric materials is provided. The process broadly comprises the steps of providing a cylinder having an interior space, positioning at least one sheet of elastomeric material within the interior space, placing a piston with a through hole into the cylinder to apply a holding force to apply a holding force to the at least one sheet, and immersing the cylinder with the at least one sheet and the piston into a test medium in which the chemical attack is to be assessed.